import numpy as np
import cv2

image_path = "6.jpg"
image = cv2.imread(image_path)

gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray = cv2.bitwise_not(gray)
thresh = cv2.threshold(gray, 0, 255,
                       cv2.THRESH_BINARY | cv2.THRESH_OTSU)[1]
coords = np.column_stack(np.where(thresh > 0))
angle = cv2.minAreaRect(coords)[-1]
if angle > 45:
    angle = 90 - angle
else:
    angle = -angle


(h, w) = image.shape[:2]
(cX, cY) = (w // 2, h // 2)

# 提取旋转矩阵 sin cos
M = cv2.getRotationMatrix2D((cX, cY), angle, 1.0)
cos = np.abs(M[0, 0])
sin = np.abs(M[0, 1])

# 计算图像的新边界尺寸
nW = int((h * sin) + (w * cos))
#     nH = int((h * cos) + (w * sin))
nH = h

# 调整旋转矩阵
M[0, 2] += (nW / 2) - cX
M[1, 2] += (nH / 2) - cY

rotated=cv2.warpAffine(image, M, (nW, nH), flags=cv2.INTER_CUBIC, borderMode=cv2.BORDER_REPLICATE)


cv2.putText(rotated, "angle: {:.2f} ".format(angle),
            (10, 30), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 255), 2)


cv2.imshow("imput", image)
cv2.imshow("output", rotated)
cv2.waitKey(0)
